Arc lamp for a weathermeter and provided with magnet means

ABSTRACT

An improved arc lamp, particularly for use in a weathermeter. In order to prevent the ashes from the combustion of the carbon electrodes from adhering to the inside of the glass globe of the conventional lamp, the electrode support plate at the top of the globe has a series of magnets placed thereon inside the globe, so that the ashes are collected in the vicinities of the magnetic poles of the magnets instead of being diffused throughout the globe.

United States Patent Suga 1 Dec. 2, 1975 15 1 ARC LAMP FOR A WEATHERMETER AND 1.153.284 9/1915 Bcechlyn 240/112 A PRO WITH MAGNET MEANS 1.205.725 11/1916 Ferber ct a1. 240/112 A 1.281.527 10/1918 Darrel 240/112 A 1 1 Inventor: ShIgeru S g Y y g 5-2 2.224.816 12/1940 Ham 240/112 A Shibuya. Tokyo, Japan [22] Fied; Jam 14, 1975 Primary Examiner loseph F. Peters. Jr.

Attorney. Agent, or FirmWenderoth, Lind & Ponack [21] Appl. No.1 540,974

1 1 ABSTRACT Foreign Application Priority Data An improved arc lamp. particularly for use in a wea- Oct. 3. 1974 Japan 49-113354 h rmeter. In order to prevent the ashes from the combustion of the carbon electrodes from adhering to [52] U.S. Cl 240/11.2 A; 314/20; 314/130 the inside of the glass globe of the conventional lamp, [51] Int. Cl. F21K 5/00 the electrode support plate at the top of the globe has [58] Field of Search 240/1 1.2 A; 314/20, 130 a series of magnets placed thereon inside the globe, so that the ashes are collected in the vicinities of the [56] References Cited magnetic poles of the magnets instead of being dil UNITED STATES PATENTS fused throughout the globe.

674.642 5/1901 Ball 240/1 1.2 A

3 Claims, 5 Drawing Figures I I n n n I I I I I1 I 5 US. Patent Dec. 2, 1975 FIGA (PRIOR ART) 1 ARC LAMP FOR'A WEATHERMETERAND PROVIDED WITI-I'MAGNET MEANS This inventionfrelates to an-improvedarc lamp suitable for us'e'as a light'source' for a weathermeter, and

particularly to an arc lamp'provided with one or a plu rality of magnetsdisposed ina radiation portion of the lamp and which magnet or magnets act to lessen the adhesion of the ashes from the radiation portion onto the glass glove enveloping the radiation portion, thereby to prevent the gradual dimming of the lamp as the conibustion of the carbon electrodes proceeds, and which makes it possible for the lamp to irradiate a constant amount of light.

In a conventional arc lamp, the ashes produced by the combustion of the carbon electrodes or other impurities in the electrodes are spread throughout most of the interior of the globe of the lamp, and they adhere to the inner surface of the glass of the globe. Eventually, all of the surface of the globe will have ashes thereon, thereby reducing the intensity of the light emitted through the globe.

The object of the present invention is to eliminate the above disadvantage of the prior art are lamp and to provide an arc lamp having a magnet disposed on the inner surface of the support plate thereof for arresting the plasma generated by the carbon arc discharge in the vicinities of the poles of the magnet for collecting the ashes produced by the combustion of the carbon electrodes without scattering them to prevent their adhesion onto the light transmitting portion of the glass globe so that the transmitted light remains undimmed.

The invention will now be described in greater detail in the following specification with reference to the accompanying drawings, in which:

FIG. 1 is a sectional elevation view of a conventional arc lamp for use in a weathermeter;

FIG. 2 is an enlarged section, partly broken away, showing the discharge radiation in a conventional arc lamp;

FIG. 3 is a perspective view, taken from below, of an arc lamp of the present invention provided with magnets;

FIG. 4 is a view similar to FIG. 2 showing the discharge radiation in the arc lamp of the present invention; and

FIG. 5 shows one example of the arrangement of the magnets in the arc lamp of FIG. 3.

In a conventional arc lamp, shown in FIG. 1, there is a radiation portion 1 which includes an upper carbon electrode 2, a lower carbon electrode 3, and a glass globe 4 joined with a support plate 5 by means of a spring 6; and an automatic ignition and control device 7. At the start of operation, the upper carbon electrode 2 is lowered so that it contacts the lower electrode. When a current flows through an electrical circuit, the upper electrode 2 is pulled up by the control device, mainly by the function of the magnetic coil incorporated in the control device, causing an electric discharge between the electrodes at a prescribed current and voltage level so as to produce visible light. Reference numeral 8 designates a gas-tight bushing through which the electrode 2 is freely moved for keeping the interior of the radiation portion sealed in gas-tight relation to the outer atmosphere.

Ashes are produced by the combustion of the carbon electrodes or the other impurities contained therein and adhere to the glass globe during the course of the ignition. As shown in FIG. 2, ashes scattered from the arcing portion spread during their flight as represented by the dots in the drawings and adhere to the inner surface of the glass globe 4. The whole surface of the glass globe will eventually be stained since the arcing portion moves as the electrodes are consumed. Further, the diffusion area AB of the ashes generally corresponds to the light transmitting area XY, so that the intensity of the transmitted light is reduced. I

FIG. 3 shows an arc lamp of the present invention seen in perspective from below, which comprises a support plate 5, a lower electrode 3, an upper electrode 2, a glass globe 4, a gas-tight bushing 8, and a control device 7 including a magnet coil, all the same as or similar to the prior art are lamp. In addition, the arc lamp has a plurality of magnets 9 shaped in the form of a letter U and attached on the surface of the support plate within the globe 4, for instance, by the means of bolts and nuts. As shown in FIG. 5, the magnets are arranged at substantially equal angular intervals around the electrodes with the N-poles and the S-poles of the magnets alternatively disposed.

In the specific embodiment shown in FIG. 5, the magnets are attached on the support plate by bolts 12, which are inserted through the holes 10 provided at the central portions of the magnets, and nuts 13 holding the magnets on the bolts. The other ends of the bolts 12 are inserted through the holes 11 provided in the periphery of the support plate to be attached hereto. However, the magnets may be attached to the support plate by any other method, for example, by the means of metal fittings crossing the central portions of the magnets.

Referring now to FIG. 4 which shows the discharge in the arc lamp of the present invention, the plasma generated by the arcing is drawn toward the vicinities of the poles of the magnets as shown by the arrows in the figure. The ashes produced by the combustion of the electrodes and including, for example, silicon oxide, silicon carbide, potassium and/or iron, float in the magnetic field and are thus ionized thereby to be attracted by the magnets. As a result, the ashes are not scattered as in the case of the conventional arc lamp, but adhere only to the poles of the magnets and the glass globe adjacent to the magnets. The transmitted light is not dimmed after the lamp has been used for a long period of time, since the ashes do not adhere to the light transmitting portion XY of the lamp.

Both the arc lamp of the present invention and the conventional arc lamp are particularly suitable to be incorporated in a weathermeter and weather tests have been conducted on the lamps with the aim of comparing them. The test results show that for the lamp of the invention, intensity of the transmitted light is increased by about 30% as compared to the conventional arc lamp, and the surfaces of specimens are uniformly irradiated to give precise test results when the arc lamp of the present invention is employed.

What is claimed is:

1. In an arc lamp, particularly for use in a Weathermeter, and having a radiation portion which includes a glass globe, carbon electrodes within the globe one of which is movable, an electrode support plate covering the globe and having a gas-tight bushing therein through which the movable electrode extends, the improvement comprising magnet means disposed on the inner surface of said support plate within said globe for 2. The improvement as claimed in claim 1 in which said magnet means is a plurality of magnets.

3. The improvement as claimed in claim 2 in which said magnets are U-shaped magnets with the poles thereof extending outwardly of the lamp and said magnets being spaced evenly around said support plates. 

1. In an arc lamp, particularly for use in a weathermeter, and having a radiation portion which includes a glass globe, carbon electrodes within the globe one of which is movable, an electrode support plate covering the globe and having a gas-tight bushing therein through which the movable electrode extends, the improvement comprising magnet means disposed on the inner surface of said support plate within said globe for collecting in the vicinities of the magnetic poles of said magnet means ashes being produced by the combustion of said carbon electrodes during the carbon arc discharge radiation to prevent diffusion of said ashes and prevEnting adhesion of said ashes to light transmitting portions of said glass globe, thereby obtaining undimmed transmitted light.
 2. The improvement as claimed in claim 1 in which said magnet means is a plurality of magnets.
 3. The improvement as claimed in claim 2 in which said magnets are U-shaped magnets with the poles thereof extending outwardly of the lamp and said magnets being spaced evenly around said support plates. 